Wood chippers are used to reduce branches, trees, brush, and other bulk wood products into small wood chips. A wood chipper typically includes an infeed chute, a feed system for controlling the feed rate of wood products into the chipper, a wood chipping mechanism, a drive system for powering the feed system and the chipping mechanism, and a discharge chute. The infeed chute is typically a funnel-shaped conduit with a wide opening which tapers towards the feed system, converging the wood products towards the chipping mechanism. Through the operation of the feed system, wood products are brought into contact with the chipping mechanism, which grinds, flails, or cuts the wood products into small pieces. These wood chips are propelled into the discharge chute and expelled from the wood chipper. Wood chippers, if operated incorrectly, are potentially dangerous devices. The chipping mechanism typically rotates at high speeds, producing the high torque necessary to chip wood products. The feed system, located at the narrowest point of the infeed chute, is a dangerous area which may catch an operator's clothing or, more importantly, an operator's limb if he or she improperly reaches into the infeed chute during operation of the wood chipper.
Existing wood chippers incorporate a number of safety devices designed to prevent such accidents and interrupt or reverse chipper motive operation should they occur. Such devices include, for example, warning labels, a safety bar which an operator may push, in the feed direction of the wood chipper, if he or she becomes caught by the feed system or cutting mechanism, and various cords/handles which hang inside the infeed chute. Although marginally effective, these safety devices suffer from the fact that their effectiveness is limited by the inattentiveness of an operator and that they are difficult to operate in an emergency situation.